Between 1957 and 1977, the Hasanlu Project conducted a series of excavations and surveys on a number of sites in the Ushnu-Solduz valley in north-western Iran. The goal of the research was to reconstruct the cultural history of the region from the first Neolithic settlements to the conquest of Persia by Alexander the Great in the 4th century BCE. The project took its name from the most important of the sites it excavated: Tepe Hasanlu. Excavations at Tepe Hasanlu uncovered an extensive burned level, the result of a destruction event sometime in the Iron Age, offering a unique picture of the life of a large settlement in this period.